Influência da adição simultânea de TiB nas propriedades térmicas, magnéticas e microestruturais de uma liga CuAlMn

Abstract

In the present work, the influence of simultaneous Ti and B doping on the thermomechanical, structural and magnetic properties of Heusler CuAlMn alloys was investigated. The samples were prepared by induction casting and characterized by X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA), Optical Microscopy (OM), Scanning Electron Microscopy (SEM), microhardness and magnetometry tests. The alloys presented the austenitic phase with L21 + DO3 structures. It was found that TiB doping reduced the average grain size and increased the amount of second-phase precipitates, which was attributed to the low solubility of Ti in the austenitic matrix. A reduction in Curie temperature, melting temperature, melting enthalpy and HV microhardness values was observed with TiB doping for the ternary CuMnAl system. It was also verified that the simultaneous doping of Ti and B changed the magnetic behavior of the CuAlMn system from paramagnetic (with weak ferromagnetic contribution) to ferromagnetic. Our results bring to light a new alternative for doping CuAlMn alloy, which, in addition to improving the structural and magnetic properties, presents interesting parameters for technological applications.